Piotr Naskrecki / Angolan free-tailed bat (Mops condylurus) close up of teeth. Codzo Caves, Mazamba, Sofala, Mozambique. Controlled conditions

Piotr Naskrecki / Angolan free-tailed bat (Mops condylurus) close up of teeth. Codzo Caves, Mazamba, Sofala, Mozambique. Controlled conditions

Huw Cordey / Mexican free-tailed bats (Tadarida brasiliensis) emerging from Bracken Cave, Texas. Over 15 million bats are thought to live in this cave, making it the greatest concentration of mammals on the planet...

Philip Dalton / Mexican free-tailed bats (Tadarida brasiliensis) flying from / to Bracken Cave and Echert James Bat Caves, Texas, USA

Philip Dalton / Mexican free-tailed bats (Tadarida brasiliensis) flying from Bracken Cave and Echert James Bat Caves, Texas, USA

Philip Dalton / Red tailed hawk {Buteo jamaicensis} flying amongst and predating on Mexican free-tailed bats (Tadarida brasiliensis) flying from / to Bracken Cave and Echert James Bat Caves, Texas, USA

Philip Dalton / Red tailed hawk {Buteo jamaicensis} flying amongst and predating on Mexican free-tailed bats (Tadarida brasiliensis) flying from / to Bracken Cave and Echert James Bat Caves, Texas, USA

David Kjaer / Mexican Free-tailed Bat (Tadarida brasiliensis mexicana) emerging at dusk from Frio Cave, near Concan in the Texas Hill Country, Texas, USA.

Karine Aigner / Woman with arms in air enjoying emergence of millions of Mexican free-tailed bats (Tadarida brasiliensis) at dusk. Bracken Bat Cave, San Antonio, Texas. June 2016.

Claudio Contreras / Broad-eared bat (Nyctinomops laticaudatus) group coming out of the cave to feed at dusk, Calakmul Biosphere Reserve, Yucatan Peninsula, Mexico, August

Claudio Contreras / Broad-eared bat (Nyctinomops laticaudatus) group coming out of the cave to feed at dusk, Calakmul Biosphere Reserve, Yucatan Peninsula, Mexico, August

Piotr Naskrecki / Ansorge's free-tailed bat (Chaerephon ansorgei) in flight, Codzo Caves, Mazamba, Sofala, Mozambique. Controlled conditions